Today's Message Index:
----------------------
1. 04:27 AM - Safety wire? (Grant Corriveau)
2. 05:35 AM - Re: Safety wire? (Ken)
3. 05:45 AM - Re: Safety wire? (Hans Teijgeler)
4. 06:30 AM - Re: Safety wire?( Kiss principle) (Daniel Tappan)
5. 06:59 AM - Re: Safety wire?( Kiss principle) (Hans Teijgeler)
6. 07:15 AM - Re: Safety wire?( Kiss principle) (Joe Healy)
7. 07:45 AM - Re: Safety wire?( Kiss principle) (Hans Teijgeler)
8. 09:02 AM - Re: Safety wire? (AI Nut)
9. 08:49 PM - Re: Safety wire? (Mike)
Message 1
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--> Engines-List message posted by: Grant Corriveau <grantc@ca.inter.net>
> There seems to be two schools of thought about safety wire. One says lay one
> strand
> of the wire over the bolt head, the other says warp both strands (twisted)
> around the bolt head (obviously in the direction to prevent backing out.)
Thanks for raising this and to the person who supplied the .pdf on the
topic. For those of us with auto-conversions, here's a couple of other
ideas for safety-wiring that my inspector recommended:
1/ Radiator cap
2/ hose clamps - a strand of safety wire across the slot of the screw to
prevent any backing off from vibes.
3/ On any taps or drains in the water jacket on the engine block
4/ Also, he strongly recommended safety wires on the oil filter and oil pan
drain plug. I have a temp sensor installed in the oil pan plug, so I
accomplished these two by putting hose clamps on them, then safetying these
clamps together so neither should be able to spin out.
5/ He strongly recommended some sort of spring or clamp to prevent the
dipstick from popping out.
6/ Any other particularly critical bolts -- i.e. someone else with a CAM100
had a bolt from the camshaft cover come loose and fall into the PSRU drive
belt -- much noise, adrenalin and 'damaged shorts' in flight and an
expensive drive belt to replace... So I took the hint and drilled these bolt
heads and safetied them too.
fwiw
--
Grant Corriveau
C-GHTF / HDS / CAM100
Message 2
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| Subject: | Re: Safety wire? |
--> Engines-List message posted by: Ken <klehman@albedo.net>
Thanks for the comments Grant.
I'll take another look but there are hundreds of bolts that have never
come loose on a car engine. Some have loc-tite. The bigger risk with
many is that they will break off when you want to remove them IMO. I've
always wondered where to draw the line on safety wire especially since
in most cases all it really does is prevent a bolt from falling out. If
it is going to loosen, safety wire is unlikely to stop the underlying
problem on a car engine. The inspectors are used to Lyc's that vibrate
hugely compared to our engines and that use gaskets instead of RTV...
I've seen some intallations that had serious design weakness's but were
well safety wired - presumably to cover the inspectors conscience (and
other things)...
Ken
Message 3
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--> Engines-List message posted by: "Hans Teijgeler" <hans@jodel.com>
In what respect do we use auto engines differently than in automotive use, I
wonder? They work a bit harder than US/Canada everyday use, but I can assure
you that the Subaru in my Jodel has an easier life than the engine in my car
(you've got the love the German Autobahns).
Billions of hours annually of automotive hours have taught us that certain
things simply do not happen. Why then modify them for use in aircraft?
> 1/ Radiator cap
Result: You don't open the cap quite as often as you could. Counter
productive, if you ask me
> 2/ hose clamps - a strand of safety wire across the slot of the screw to
> prevent any backing off from vibes.
Nothing against doing this, other than that it really is not necessary. Ever
tried to remove a water hose, even with the hose clamp removed? Usually a
total loss affair, when you end up cutting the hose to get the bloody thing
off.
> 3/ On any taps or drains in the water jacket on the engine block
Paranoia is the right word for this, if you ask me.
> 4/ Also, he strongly recommended safety wires on the oil filter and oil
> pan
> drain plug. I have a temp sensor installed in the oil pan plug, so I
> accomplished these two by putting hose clamps on them, then safetying
> these
> clamps together so neither should be able to spin out.
>
> 5/ He strongly recommended some sort of spring or clamp to prevent the
> dipstick from popping out.
This one is the killer for me. Just yesterday, a friend of mine commented
the same.
My thoughts:
A - why would the dipstick want to pop up? Even if the engine core is
pressurized (in which case you have very different problems) AND the core
ventilation has become clogged somehow, and the core pressure is large
enough to overcome the friction of the dipstick, then still the dipstick
will only pop up a quarter inch or so for the pressure to be released. I see
no other physical forces in play that can magically lift the dipstick.
B - Even if magic was there, then where would that dipstick go, with the
cowling less than two inches above it?
C - What if it did pop up? No oil would be spraying out or anything.
>
> 6/ Any other particularly critical bolts -- i.e. someone else with a
> CAM100
> had a bolt from the camshaft cover come loose and fall into the PSRU drive
> belt -- much noise, adrenalin and 'damaged shorts' in flight and an
> expensive drive belt to replace... So I took the hint and drilled these
> bolt
> heads and safetied them too.
>
Fair enough.
> fwiw
> --
> Grant Corriveau
> C-GHTF / HDS / CAM100
>
Of course, whatever floats your boat is okay, but what's wrong with "if it
ain't broke, don't fix it"?
You are adding weight and complexity, you are making maintenance potentially
more difficult and all that because we still compare automotive engines to
aircraft engines.
Just my 2 cents of course...
Hans
Message 4
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| Subject: | Safety wire?( Kiss principle) |
--> Engines-List message posted by: Daniel Tappan <dancfi@yahoo.com>
Hans Teijgeler <hans@jodel.com> wrote:
--> Engines-List message posted by: "Hans Teijgeler"
In what respect do we use auto engines differently than in automotive use, I
wonder? They work a bit harder than US/Canada everyday use, but I can assure
you that the Subaru in my Jodel has an easier life than the engine in my car
(you've got the love the German Autobahns).
I am a somewhat senior aviation mechanic and am used to safety wiring everything.
I read Hans's post and hate to admit it but everything you said Hans made perfect
sence. You are correct. Keep it simple!
---------------------------------
Message 5
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| Subject: | Safety wire?( Kiss principle) |
--> Engines-List message posted by: "Hans Teijgeler" <hans@jodel.com>
Daniel,
I understand that it is hard to break with an old habit :-)
But cheer up! At least we are actually looking at the engine closely with
this in mind, rather than just assuming that it will be okay (or the
opposite: that it will not, and thus needs to be safety-wired).
Being conscious about something is a good thing.
For one, I see the merits in safety-wiring the oil drain plug and the oil
temp sensor in the oil pan. Oil is too important for the engine for me to
trust friction alone on these items. Plus if the plug falls out, I'll lose
all oil in very short order.
The oil filter? Tough one. They don't fall off on auto engines (on the
contrary - they are usually pigs to remove), but safety wire is cheap
insurance here. On my NSI Subaru, there is not enough room for safety wire,
so I'll leave mine as is without losing sleep over it.
The dip stick? No harm done if it comes loose, so leave it alone.
A complete loss of engine coolant, I can handle. I can reduce the power
setting to best glide speed at level flight and coast to the nearest
airfield. Depending on your cowling, a typical water cooled engine still
loses about 35% of its heat through air cooling. And even when overheating,
the only hurt is in my wallet for an overhaul. No crashing imminent.
Mounting bolts: losing the engine in flight (as in: bolts came lose and
engine dropping down) means certain death. So safety them (with cotter pins)
and double check everything. I'd rather lose my ailerons or elevator than my
engine!
Air filter? Let it come loose. No harm done, other than possible ingestion
of some dust. No need for safety wire.
Perhaps it is not such a bad idea to have a very good look at what the
racing guys do, and why. They typically use the same engines as we do, are
very weight and maintenance conscious, and work their engines at least as
hard as we do. Learn from where the knowledge is.
Hans
> -----Original Message-----
> From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-
> server@matronics.com] On Behalf Of Daniel Tappan
> Sent: zaterdag 22 oktober 2005 15:30
> To: engines-list@matronics.com
> Subject: RE: Engines-List: Safety wire?( Kiss principle)
>
> --> Engines-List message posted by: Daniel Tappan <dancfi@yahoo.com>
>
>
> Hans Teijgeler <hans@jodel.com> wrote:
> --> Engines-List message posted by: "Hans Teijgeler"
>
> In what respect do we use auto engines differently than in automotive use,
> I
> wonder? They work a bit harder than US/Canada everyday use, but I can
> assure
> you that the Subaru in my Jodel has an easier life than the engine in my
> car
> (you've got the love the German Autobahns).
>
>
> I am a somewhat senior aviation mechanic and am used to safety wiring
> everything.
>
> I read Hans's post and hate to admit it but everything you said Hans made
> perfect sence. You are correct. Keep it simple!
>
>
>
>
>
> ---------------------------------
>
>
>
>
>
Message 6
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| Subject: | Re: Safety wire?( Kiss principle) |
--> Engines-List message posted by: "Joe Healy" <jhealy@socal.rr.com>
Don't overlook the fact that aircraft engines operate across a VERY wide
range of temperature and humidity extremes compared to what auto engines due
to changes in altitude on each flight. This can cause PCV valves to freeze
solid resulting in extreme engine pressure. It sets up thermal fatigue
stress, etc.
The reasoning below (what's the difference between auto and airplane engine
operation) might be OK for light sport experimentals that never fly more
than a few thousand feet above ground level. But the arguments break down
for machines capable of higher altitude performance.
Airplane engines also operate at constant RPM's for extended periods of
time. Therefore, if a natural vibration frequency is inadvertently reached
at cruise speed on a particular item, your going to want that wired. The
problem is that you can never be sure where this will occur.
do not archive.
J. Healy
----- Original Message -----
From: "Daniel Tappan" <dancfi@yahoo.com>
Subject: RE: Engines-List: Safety wire?( Kiss principle)
> --> Engines-List message posted by: Daniel Tappan <dancfi@yahoo.com>
>
>
> Hans Teijgeler <hans@jodel.com> wrote:
> --> Engines-List message posted by: "Hans Teijgeler"
>
> In what respect do we use auto engines differently than in automotive use,
I
> wonder? They work a bit harder than US/Canada everyday use, but I can
assure
> you that the Subaru in my Jodel has an easier life than the engine in my
car
> (you've got the love the German Autobahns).
>
>
> I am a somewhat senior aviation mechanic and am used to safety wiring
everything.
>
> I read Hans's post and hate to admit it but everything you said Hans made
perfect sence. You are correct. Keep it simple!
>
>
> ---------------------------------
>
>
Message 7
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| Subject: | Safety wire?( Kiss principle) |
--> Engines-List message posted by: "Hans Teijgeler" <hans@jodel.com>
>
> Don't overlook the fact that aircraft engines operate across a VERY wide
> range of temperature and humidity extremes compared to what auto engines
> due
> to changes in altitude on each flight. This can cause PCV valves to
> freeze
> solid resulting in extreme engine pressure. It sets up thermal fatigue
> stress, etc.
I've got no PCV valves to freeze over, plus I can assure you that it is warm
in the engine compartment, even at altitude!
The butterfly valve (aka throttle) of my engine is water-heated, as is the
original Subaru unit.
Having said that, I am planning to do the test flying with my new engine
(own EJ-25 conversion is out, NSI EJ-25 conversion in) at various altitudes
while recording temps from several temperature probes in my engine
compartment.
> The reasoning below (what's the difference between auto and airplane
> engine
> operation) might be OK for light sport experimentals that never fly more
> than a few thousand feet above ground level. But the arguments break down
> for machines capable of higher altitude performance.
The highest I've taken my car was to 10,000 ft. No problems there, but
you've got a good point that this is something to keep in mind while looking
for problem areas in any engine.
In Europe, it is rare to fly any single engine GA aircraft over 7000ft or
so, and the nearest mountain is five hours flying away from here, so for me
this is not really an issue.
If I were to regularly fly in high and really cold environments, I'd think
of adjustable cowl flaps though. I have noticed that prolonged power-off
descends would get the water temperature on my engine below the 195 F
thermostat value, with oil temps following suit. Not a real problem, and
nothing compared to the shock cooling issues of an air cooled engine, but
certainly something to keep in mind when leveling off.
> Airplane engines also operate at constant RPM's for extended periods of
> time. Therefore, if a natural vibration frequency is inadvertently reached
> at cruise speed on a particular item, your going to want that wired. The
> problem is that you can never be sure where this will occur.
My car's got cruise control, so I frankly fail to see how this differs. This
is one of the areas where one can profit from the millions of dollars /
billions of yen's invested in engineering these engines. The natural
frequencies of the parts that are bolted to these engines are designed to
fall outside the normal operating range, or else the part is beefed up to
the extend that it can withstand the resonance.
And like Ken said: don't compare the resonances of these engines to those on
Lycomings. I can put a glass of water on top of the engine and rev it up to
my hearts delight without having to fear for the glass (only for the prop
blast to blow it off maybe)
> do not archive.
Why not? You've got good points!
Hans
>
> J. Healy
> ----- Original Message -----
> From: "Daniel Tappan" <dancfi@yahoo.com>
> To: <engines-list@matronics.com>
> Subject: RE: Engines-List: Safety wire?( Kiss principle)
>
>
> > --> Engines-List message posted by: Daniel Tappan <dancfi@yahoo.com>
> >
> >
> > Hans Teijgeler <hans@jodel.com> wrote:
> > --> Engines-List message posted by: "Hans Teijgeler"
> >
> > In what respect do we use auto engines differently than in automotive
> use,
> I
> > wonder? They work a bit harder than US/Canada everyday use, but I can
> assure
> > you that the Subaru in my Jodel has an easier life than the engine in my
> car
> > (you've got the love the German Autobahns).
> >
> >
> > I am a somewhat senior aviation mechanic and am used to safety wiring
> everything.
> >
> > I read Hans's post and hate to admit it but everything you said Hans
> made
> perfect sence. You are correct. Keep it simple!
> >
> >
> > ---------------------------------
> >
> >
>
>
>
>
>
Message 8
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| Subject: | Re: Safety wire? |
--> Engines-List message posted by: AI Nut <ainut@hiwaay.net>
Because it does come out, and spew oil out. High vibration engines,
like diesels, do this especially when you don't screw down the tightener
like you're supposed to. The Lycs and Continentals vibrate as much or
more than a diesel. Best 1930's technology you can buy today.
David M.
Hans Teijgeler wrote:
>--> Engines-List message posted by: "Hans Teijgeler" <hans@jodel.com>
>
>In what respect do we use auto engines differently than in automotive use, I
>wonder? They work a bit harder than US/Canada everyday use, but I can assure
>you that the Subaru in my Jodel has an easier life than the engine in my car
>(you've got the love the German Autobahns).
>
>Billions of hours annually of automotive hours have taught us that certain
>things simply do not happen. Why then modify them for use in aircraft?
>
>
>
>>5/ He strongly recommended some sort of spring or clamp to prevent the
>>dipstick from popping out.
>>
>>
>
>This one is the killer for me. Just yesterday, a friend of mine commented
>the same.
>
>My thoughts:
>
>A - why would the dipstick want to pop up? Even if the engine core is
>pressurized (in which case you have very different problems) AND the core
>ventilation has become clogged somehow, and the core pressure is large
>enough to overcome the friction of the dipstick, then still the dipstick
>will only pop up a quarter inch or so for the pressure to be released. I see
>no other physical forces in play that can magically lift the dipstick.
>B - Even if magic was there, then where would that dipstick go, with the
>cowling less than two inches above it?
>C - What if it did pop up? No oil would be spraying out or anything.
>
>
>
Message 9
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--> Engines-List message posted by: "Mike" <mlas@cox.net>
I only have a few things to say on the subject of safety wire, first it
is your airplane and it is your experiment. Therefore you can do it
what ever way you want. You can do like the factory airplanes and
safety wire almost everything, or like a road car nothing at all. But
keep this in mind, some night you may be flying over eastern AZ or NM
and your oil filter or the likes may loosen up and cause and engine
failure. Was the extra headache, the $10, or the pin prick to the
finger worth it? I'll let you decide.
As far as cars and safety wire, in every form of regulated racing safety
wire is required.
Mike Larkin
TS-11 Iskra
A-320
Lancair Legacy
Kitfox 4
25 year pilot
22 year aircraft mechanic
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